Active muscles demand huge amounts of oxygen, and the circulatory system works hard to provide it. Blood carries oxygen to the muscles. When the body is at rest, blood carries nutrients to the muscles so that they can repair and rebuild themselves. Blood also carries away the waste products that hard-working muscles produce, back out through the lungs to be filtered.
so they Circulatory system xx muscular system :)
<span>Her data suggested that DNA is a helical structure that has two strands attached in the middle by the phosphate bases. That was the necessary information, needed to complete an accurate model of the structure of DNA. She also was the first one to announce that the phosphate units are located in the external part of the DNA and that the amount of water found in the molecule is in accordance with other parts of it.</span>
